Just hydras is easily beaten by mass roach. Lings fair well against them too. But, if their Roach: Hydra ratio is 50:50 and you just went 100% roach you will win all midgame battles as long as your econs are similar.

Just make sure to eventually transition into a 3:2 roach hydra composition (very slowly) or grab mutas.

That being said I have never played a zvz where it got past roach v. roach with some hydras sprinkled in.

You can also do infestorbaneling, it is a good strategy if you fungal growth and rush the hydra with banelings. Banelings do heaps of dmg to hydras as they are bio and hydras are usually clumped together as it is their strongest point.
4Gate can be stopped by roach/hydra, ling/roach/infestor. Basically depends on what the composition of the 4gate is.

Roach hydralisk will beat pure hydralisk off creep. It is also a very strong amry composition in a zerg vs zerg. Pure roaches is also pretty good, however, this depends whether you have creep and the roach speed upgrade.

Btw Infestor baneling is an interesting way of dealing with hydras but players rarely go 100% hydras so unless you are sure they are sticking to one unit I would avoid infestors.

In ZvZ I can almost never suggest going infestors. Just teching to infestors costs 5 roaches or an attack upgrade. In a mirror matchup that is HUGE. I've seen it used successfully in Scrap Station i.e. the longest possible rush distance. Making that work is something only top tier players can do and even they tend to mudd it up.

Infestors always help no matter what. It's always good to throw a splash of infestors into your army mix just like terran throwing a splash of ghosts or protoss throwing a splash of high templars into their army mix. Just having a few infestors can boost your advantage in a battle. Fungal growth and/or infested terran spawn can swing battles in your favor. Infested terrans are free renewable armies, do bonus damage to armor and can make good meat shields.

Haha some interesting comments there XD but yea I think that about all thats been listed. In general I would expect them to go roach hydra, however if its just pure hydras, as people said:

> Roaches tank hydras to hell, its really really bad, however hydras outrange roaches so just be careful, as youll have 1 line of roach firing, but 3 lines of hydra firing, so make sure its still a roach hydra mix you use.

> Banelings, but I would only suggest this if you already have the tech there or have thrown it down anyway, and have bling speed researched, this is because of hydras high DPS, because of the high firing rate, which means they will target fire your blings to hell.

Also, you need infestors to get to hive tech regardless, so when you have the spare resources go for it, get the glands research for starting energy and then you can pump a couple out, remember, fungal does damage over time, paralysis and this means your units will plow through them. Another overlooked feature of fungal is that it will split your opponents army, and force them to either cut their losses or engage at a disadvantage. In other words, the only excuse ive ever had not to get them is if my micro has gone to shit that day lol.

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